Is this a weed?

I'm wondering whether this is a weed. I know I planted something but can't remember. My confusion is that it might be something that birds planted which has grown.mplease help as I might be nurturing a weed.

my neighbourgrows this for his birds. Some of his best specimens are taller than me. Not surprising I have lots germinating in the garden every year. It's not a lot of trouble though. Quite attractive in its leafy stage